Electromyograph (EMG)-controlled neuromuscular electrical stimulation is a rehabilitation technique which allows volitional activation of specific motion patterns in the paretic limbs of stroke survivors. This type of active training has been shown more effective for post-stroke motor relearning than passive exercises provided with conventional therapy. However, the limited sensitivity and selectivity of surface electrodes in detecting weak EMG signals and activating specific muscles, and the pain caused by skin-surface stimulation have hindered the clinical implementation of this promising technique. The propose of this project is to develop an intramuscular sensing-stimulation device that will increase the probability of detecting adequate EMG signal in a paretic limb, increase muscle specificity during stimulation and decrease stimulation- induced discomfort. A tripolar, coiled electrode will be developed for implementing both sensing and stimulation functions. The electrode will be inserted into the muscle with a needle carrier and maintained in the location for several weeks. Electronic circuits will also be developed for extracting weak EMG signals from strong stimulation interference, and for generating current pulses suitable for intramuscular stimulation. The pre- prototype device will be tested in a small number of hemiplegic patients to evaluate the design concept and device performance. PROPOSED COMMERCIAL APPLICATION: The device developed by this project can be used in the rehabilitation process of many hemiplegic patients. The training realized with this device is expected to accelerate recovery, shorten hospitalization period, reduce attendant needs, and thus improve patients' quality of life and lower medical care cost.